Trained to kill from childhood, siblings Bannon and Vree have only known life as assassins in the Imperial Army. The army is both their mother and father, their lives subject to the whims of the Crown. When their latest target steals Bannon's body for his own, Vree saves her brother by dragging his spirit in to share hers. But two assassins in one body is one assassin too many. To save both their lives, they must abandon the only life they’ve known, risking Imperial ire and possible execution, to regain Bannon’s body. It isn't until after they capture Gyhard, the body thief, that they realize they can't force him to do anything while he holds Bannon's body hostage. But Gyhard is willing to trade Bannon's body for their assistance. All they have to do – while being hunted for desertion and dealing with an unknown power able to Sing the dead out of the grave – is betray the oaths they've lived by and help Gyhard secure the body of an Imperial Prince.